Hello, I have a 99 5.4 4x4/awd eddie bauer edition expedition. The trans was flawless when driving and I replaced my heads..(and all the gaskets from heads up) and immediately after doing all this the transmission started to slip and would not engage in drive right away. Fluid levels are good.. Now the transmission engages right away, but shudders and or slips unless I go easy easy easy on it.. after about 20 mph it is fine.. I dont think this is an electrical issue.. but who knows.. also I checked the lines to make sure they were not bent or mangled up... ok... what do you think??

oh and 4x4 still works, and engages just fine..

when I say shudder I mean it beats the living crap out of you when you accelerate you have to drive like a turtle to avoid it.. (shudder = engage ..disengage.. engage.. disengage.. )

 

Is it a long time since you replaced and flushed the fluid on the transmission? High mileage? Other than that, since it started after the job you did, verify that all connectors are properly connected. I'm not too familiar with the first generation Expedition, but perhaps it has a throttle cable or similar that might be out of adjustment? Not sure if the transmission in the first generation has a cable for the throttle position or if it gets it electronically from the PCM like in the second generation, so hopefully someone else will chime in on that.

 

yeah the fluid is sort of old.. but I find it weird that instantly it would act up as soon as I replaced heads.. I tripple checked all connections.. nothing seems out of place.. there is no throttle related cable on the trans.. only on the intake manifold. I have no problem changing fluid..but I am trying to eliminate other things before I spend 120 dollars on fluid and a kit

 

It is weird that it started this at the same time, but it may also be a coincidence and not directly related to that job.

The best way of finding out the state of the transmission is to check the condition of the fluid and the oil pan, if there's a lot of debris in there, it may indicate that it's getting worn, or that the fluid is not flowing properly to allow it to engage as it should. If you don't want to do a complete fluid service, you could just drop the pan and inspect it, and then replace the 4-5 quarts that comes out of it.

I would also consider taking it to a shop and have the codes read to see if there's any codes on the transmission that might indicate that the problem is.

 

Correction, seems the pan of the 4R100 holds around 7-8 quarts.

 

welp... guess what I found.... I noticed the rear trailing arms were broken.. the whole axle tilts when accelerating... that would be the shudder problem I am sure.. maybe it was engaging.. and the whole axle was just twisting and it seemed like it was slipping.. Ill update when I replace the trailing arms..

 

Scary...ain't it?

 

Wow, that sounds scary! That would certainly be a problem yes.....

 

well I thought that would be it, but the problem started again today and it took almost 10 seconds before it engaged into drive.. so guess what else I found.. a glowing red catalytic converter ..which is right next to the trans.. so I am going to cut the cat off..I am thinking possibly the heat from the cat was bleeding into the trans and making the fluid expand too much??

 

Expand too much...no. But excessively heated tranny fluid will break down and cause premature wear to the tranny, if not an all out failure.

 

Well I have noticed that the problem only persists when the truck has been jacked up, or on a hill for while... tells me either the filter has sediment in it and when it settles it is not blocked, or there is a huge air bubble inside.. more towards the filter..


Another side question.. ever have oil not register on the dipstick after adding six quarts for an oil change?? Almost nothing is showing up on the dipstick.. and I just changed the oil today.. six quarts.. anything???

 

ill do a fluid and filter.. other than being parked on a hill all night.. it shifts very smooth and engages instantly.. got two upper trailing arms for 45 a piece from the junk yard.. still had all black paint on them no rust and the ford genuine sticker on them.. not a bad deal.

 

Only when it's an incorrect replacement dipstick, or it's not being inserted all the way until it snaps into place.